Spatio-temporal Modeling of chikungunya in Brazil: Interplay of Climate, Mobility, and Socioeconomic Factors

Chikungunya, transmitted by Aedes mosquitoes, has increased in Brazil, accounting for 98% of reported cases in the Americas. This study, we modeled the spatio-temporal distribution of chikungunya across the urban centroids of Brazilian municipalities from 2015 to 2024 and evaluated the effects of climatic, environmental, mobility, and socioeconomic factors. Bayesian ecological regression models with fixed and random effects were implemented in R-INLA. Overall, 1,121,705 cases were analyzed. Higher chikungunya incidence was associated with lower altitudes and the Caatinga biome. A non-linear association with temperature was observed, showing a negative relationship up to 17°C that became positive and peaked around 21°C. Initially concentrated in the northeast, chikungunya later spread toward the southeast and central-west regions of Brazil. Unexpected outbreaks during the winter suggest disruptions in seasonality. This approach underscores the importance of considering multiple interacting factors in combating vector-borne diseases, particularly in regions prone to rapid disease transmission, such as Brazil.